Mixing devices for dilution and blending of materials have been heretofore suggested and/or utilized (see U.S. Pat. Nos. 4,834,545, 3,934,859, 3,925,243, and 3,831,907). More specifically, such devices for mixing viscous liquid polymeric material and water have been heretofore suggested and/or utilized (see U.S. Pat. Nos. 5,018,871 and 5,061,456).
Because long-chain polymers (such as solution-type, or mannich, viscous liquid polyelectrolytes) have high molecular weight and viscosity, proper dilution requires turbulence and fluid shear. Excessive shear, however, can break the polymer chains and render the polymer ineffective, while insufficient shear results in unblended polymer and a non-homogeneous solution. Therefore, when blending such liquids as polymer and water, it is desirable to have the ability to control the type and amount of mixing energy applied to the polymer.
Heretofore known mixing, or blending, devices have not always proved effective for diluting and activating such solution-type polymers. Devices utilizing impellers for such blending operations can damage the polymer with excessive shear caused by rotating impeller edges. While a homogeneous solution may thus be produced, the numerous broken polymer chains exhibited can make the solution substantially less capable of serving its intended purpose (for example as a flocculant or dewatering agent). Other devices fail to optimize shear and/or blending duration, often resulting in non-homogeneous, and thus less effective, solution of polymer and solvent (such as water) in which only a smaller than desirable percentage of polymer has been diluted (leaving the remainder in clumps or fisheyes).
Thus, an improved mixing device which can apply enough mixing shear to properly disperse the polymer molecules in the solvent liquid while refraining from breaking the polymer chains and rendering them less useful could still be utilized.